About borewell motor to be purchased


I have recently dug borewell of 935 feet deep got water table at 2 stages, 1 at 570 feet stage and other at 825 feet, now what stage motor should I buy and what HP? Which company motor, and I am thinking to lower up to 850ft, have done casing for 420ft as up 500ft it's loose mud. Please advise me on stage, HP and company of pump I have to buy.